Magnetic core structure and method of assembling



July 30, 1940. 2.209,81l

MAGNETIC com: STRUCTURE AND METHOD OF ASSEMBLING R. H. DIERSTEIN Filed Sept. 3, 1938 Inventor: Roy H Dlerste'm,

b I? His gttovney.

Patented July 30, 1940 PATENT OFFICE v MAGNETIC CORE STRUCTURE AND METHOD ,OF ASSEMBLING Roy H. Dierstein, rm Wayne,Ind., mime; to General Electric Oompany, a corporation of New York Application September 3, 1938, Serial No. 228,378

Claims.

My invention relates to magnetic cores such as are used in transformers and reactors. One form of magnetic core which has been used extensively includes an outer hollow shell with a wind- Q ing leg extending across the opening and fitting so tightly between opposite sides of the shell as to hold it securely in place. The shell and the winding leg have been formed of superposed laminations, and it has been found that if the winding leg laminatio'nsare cut or punched from the same positions in the outer shell laminations that they are to occupy when assembled, then the two parts of the core will fit tightly and securely when they are forced together. The winding or windings are of course preferably placed around the winding legbefore it is forced into position in the outer shell. It has been found that when order to avoid too much damage from this cause.

The general object of the invention is to pro- :0 vide an improved magnetic core and animproved method for forming the magnetic core having awinding leg held in place by a forced fit in an outer shell, but avoiding any substantial damage to the material during the assembly.

The invention will be better understood from the following description taken in connection with the accompanying drawing in which Fig; l is a perspective view of a transformer including a magnetic core formed in accordance with the invention, and Fig; 2 is a perspective view show- .ing the transformer partially assembled and a machine or. tool for assembling it. Like reference characters indicate similar parts in both figures of the drawing.

The transformer I0 shown 'inFig. 1 includes a magneticcore II having a winding leg I2 fitting tightly between the yokes I3 and surrounded by windings I4. The outer ends of the yokes I3 are punched from the same positions which they are finally to occupy in the laminations of the yokes It so thatithey will be held securely in position when the two parts of the core are assembled.

v fiat support 20. The projections I! fit into the cient force to the block Iqto permit the windintegrallyconnected by outer legs I5 to provide The laminations including the yokes I3 are formed with notches in the outer edges ofthe yoke portions .so that when assembled these notches will be'in' alignment to form a notch I6 extending across each outer surface of the yokes. 5 The sides of the notches diverge inwardly from the outer surface of each yoke so that they may be engaged by projections IT on the inner surfaces of blocks I8 and IQ mounted on a suitable 10 notches l6 in dovetail fashion so that the blocks I8 and I9 and the yokes I3 are held securely together. The block I8 is secured to the support while the other block I9 is movable to permit it to be pulled away from the block I8 by a lever 2! to increase the spacing betweenthe yokes. The block I9 may be operated by foot or otherwise by means of a link 22. In assembling the magnetic core It, the laminatlons of the winding leg I2 are out or punched from the positions which they are finally to 00- 3 cupy between the yoke portions I3 of the outer magnetic-Ashen. The windings II are placed around the winding leg I2, and the laminations of the outer shell are dropped into place between the blocks "and I9 with their notches I6 engaged by the projections I] of the blocks. The lever 2|, which engages a rod 23 extending between opposite sides of the block I9, is operated to force the block I9 away from the block I8. forces the two projections ll of the two blocks apart and applies pulling'forces to the outer surfaces of the yokes I3 to spring theyokes I3 sufllci'ently away from each other to permit the winding leg I2 with its windings II to be placed in position between the two yokes I3 with! out the necessity of using undue force and consequently without damage to the laminations as they rub together. In some'cases it may be advisable to apply sufiicient force to the movable block I8 to spread the yokes I3 enough to permit the winding leg I2 to drop freely into place be-- tween the yokes'. It is obvious, however, that it may often .be satisfactory to apply only suming leg If to be forced 'intoposition between the yokes I3 without damage to the laminations.

Any force applied by the lever 2| to the block I9 the yokes l3 to grip the winding leg and hold it securely in place.

The invention provides not only a simple and convenient method of assembling the core parts, but an improved core as well because of the more perfect fit between the parts and the absence of injury and distortion to the edges of the laminations. The presence of the notches IS in the outer surfaces of the yokes I3 opposite the ends of the windingleg is obviously not objectionable because they do not interfere .to any substantial 1 degree with the magnetic flux in the core. The notches l6 also permit .the yokes to be easily engaged and spread apart at any time after assembly if repair or replacement of the windings is necessary.

The invention has been explained by describing and illustrating a particular transformer and a particular method of forming it, but it will be obvious that changes may be made without, departing from the spirit of the invention and the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The method of forming a magnetic core of flat stacked laminations having a winding leg and spaced integrally connected yokes with the winding leg fitting tightly between the yokes,

said method including the stps of applying pulling forces to the-outer surfaces of the yokes to increase the spacing between them, placing the winding leg between the yokes without substantial friction therebetween, and releasing the yokes to permit them to grip the winding leg.

. 2. The method of forming a magnetic core of punched and stacked laminations having spaced integrally connected yokes and a winding leg fitting tightly between the yokes, said method including the steps of applying pulling forces to the yokes to increase the spacing therebetween by edgewise distortion of the laminations, .placing the winding leg between the yokes without such friction between said leg and said yokes as to cause appreciable injury to the abutting edges of the laminatiops, and releasing the yokes to permit them to grip the winding leg.

3. A magnetic core including. a winding leg and spaced integrally connected yokes, said winding leg fitting tightly between the'yokes, and the yokes having dovetail notches across their outer surfaces.

4; A magnetic core including a winding leg and spaced integrally connected yokes, said wind- ..ing leg fitting tightly between the yokes, and

forming spaced yokes and outer core legs integrally connecting said yokes, and a winding leg fitting tightly between the yokes, the yokes hav-- ing dovetail notches across their outer surfaces.

ROY H. DIERSTEIN. 

